000K utf8 0100 1894777980 1100 2024$c2024-06-07 1500 eng 2051 10.3390/nano14120992 3000 Zahn, Diana 3010 Dellith, Jan 3010 Diegel, Marco 3010 Dutz, Silvio 3010 Valitova, Alina 4000 Magnetic barium hexaferrite nanoparticles with tunable coercivity as potential magnetic heating agents [Zahn, Diana] 4060 20 Seiten 4209 Using magnetic nanoparticles (MNPs) for extracorporeal heating applications results in higher field strength and, therefore, particles of higher coercivity can be used, compared to intracorporeal applications. In this study, we report the synthesis and characterization of barium hexa-ferrite (BaFe₁₂O₁₉) nanoparticles as potential particles for magnetic heating. Using a precipitation method followed by high-temperature calcination, we first studied the influence of varied synthesis parameters on the particles’ properties. Second, the iron-to-barium ratio (Fe/Ba = r) was varied between 2 and 12. Vibrating sample magnetometry, scanning electron microscopy and X-ray diffraction were used for characterization. A considerable influence of the calcination temperature (Tcₐl) was found on the resulting magnetic properties, with a decrease in coercivity (HC) from values above 370 kA/m for Tcₐl = 800–1000 °C to HC = 45–70 kA/m for Tcₐl = 1200 °C. We attribute this drop in HC mainly to the formation of entirely multi-domain particles at high Tcₐl. For the varying Fe/Ba ratios, increasing amounts of BaFe₂O₄ as an additional phase were detected by XRD in the small r (barium surplus) samples, lowering the particles’ magnetization. A decrease in HC was found in the increased r samples. Crystal size ranged from 47 nm to 240 nm and large agglomerates were seen in SEM images. The reported particles, due to their controllable coercivity, can be a candidate for extracorporeal heating applications in the biomedical or biotechnological field. 4950 https://doi.org/10.3390/nano14120992$xR$3Volltext$534 4961 http://uri.gbv.de/document/gvk:ppn:1894777980 5051 570 5550 barium hexaferrite 5550 coercivity 5550 hard magnetic 5550 hyperthermia 5550 magnetic nanoparticles 5550 SEM 5550 VSM 5550 XRD